FALLOPIAN TUBES. 



853 



the porous shell separates them more and more as the fluid of the egg evaporates. This air- 

 space is not found in fresh-laid eggs.] The layers consist of spontaneously coagulated keratin- 

 like fibres arranged in a spiral manner around the albumin (Lindvall and Hamarsten). [Ex- 

 ternal to this is the test, or shell, which consists of an organic matrix impregnated with lime 

 salts.] The shell consists of albumin impregnated with lime salts, which form a very porous 

 mortar. [The shell is porous, and its inner layer is perforated by vertical canals, through 

 which the respiratory exchange of the gases can take place.] In the eggs of some birds 

 there is an outer structureless, porous, slimy, or fatty cuticula. The shell is secreted in the 

 lower part of the oviduct. The shell is partly used up for the development of the bones of 

 the chick (Prout, Gruwe, although this is denied by Polt and Preyer). The pigment which 

 often occurs in many layers of the surface of the eggs of some birds appears to be a derivative of 

 hsemogloblin and biliverdin. 



Chemical Composition. The yellow yelk is alkaline, and coloured yellow owing to the pre- 

 sence of lutein, which contains iron. It contains several proteids [including a globulin body 

 called vitellin (p. 376)], a body resembling nuclein, lecithin, vitellin, glycerin-phosphoric acid, 

 cholesterin, olein, palmitin, dextrose, potassic chloride, iron, earthy phosphates, fluoric and 

 silicic acids. The presence of cerebrin, glycogen, and starch is uncertain. [Dareste states that 

 starch is present.] 



[The albumin of egg contains water, 86 per cent.; proteids, 12; fat and extractives, 1*5; 

 saline matter, including sodic and potassic chlorides, phosphates, and sulphates, "5 per cent.] 



[The uterus, a thick hollow muscular organ, is covered externally by a serous coat, and 

 lined internally by a mucous membrane, 

 while between the two is the thick mus- 

 cular coat composed of smooth muscular 

 fibres arranged in a great number of layers 

 and in different directions. The mucous 

 membrane of the body of the uterus in 

 the unimpregnated condition has no folds, 

 while the muscularis mucosae is very well 

 developed, and forms a great p aI t of 

 uterine muscular wall. The mucous 

 membrane is lined by a single layer of 

 columnar ciliated epithelium. A vertical 

 section shows the mucous membrane to 

 contain * numerous tubular glands (fig. 

 645) the uterine glands which branch 

 towards their lower ends. They have a 

 membrana propria, and are lined by a 

 single layer of ciliated epithelium, a 

 small lumen being left in the centre. 

 The utricular glands are not formed dur- 

 ing intra-uterine life (Turner), nor are 

 there any glands in the human uterus at 

 birth (G. J. Engehnann). There are. 

 numerous slit-like lymphatic spaces in 

 the mucous membrane (Leopold), which 

 communicate withwell-markedlymphatic 

 vessels existing in this and the other 

 layers of the organ. In the cervix, the 

 mucous membrane is folded, presenting 

 in the virgin the appearance known as 



the arbor vitas. The external surface of Fig. 645. 



the vaginal part of the neck is covered Vertical section of the mucous membrane of the human 

 by stratified squamous epithelium, like ut eras. e, columnar epithelium, the cilia absent ; 



fn^f^Sf'il I y, yy> utricular glands ; ct, intra-glandular connective - 



[The Fallopian tubes are really the tissue ; w, blood-vessels ; mm, muscularis mucosa;, 

 ducts of the ovaries (fig. 646). They 



consist of a serous, muscular (an external, longitudinal, and an internal circular) layer of non- 

 striped muscle, and a mucous layer thrown into many folds and lined by a single layer of 

 ciliated columnar epithelium, but no glands (fig. 647). 



434. PUBERTY. The term puberty is applied to the period at which a 

 human being becomes capable of procreating, which occurs from the 13th to 15th 

 years in the female, and the 14th to 16th in the male. In warm climates, puberty 

 may occur in girls even at 8 years of age. Towards the 40th to 50th year, the 

 procreative faculty ceases in the female with the cessation of the menses j this con- 



